An ever increasing scarcity of resources demands ever greater efforts for obtaining raw materials and sources of energy. As a result, drilling for oil and gas is conducted at ever greater ocean depths. To ensure the safety of such deep-sea drilling operations, which are implemented from drilling platforms or ships, comprehensive safety installations are provided on the ocean floor that are functionally allocated to the transitional area between the drill hole and drill pipe or delivery pipe. One important system part of the safety standard of such deep-sea drilling applications is the “blow-out preventer” (BOP), a device that causes a quick-closure of the outlet to the drill hole and/or drill pipe and/or delivery pipe, should a hazardous situation occur. To ensure safe functioning thereof, pressure fluid at a correspondingly high working pressure must be reliably provided for the hydraulic actuation.
To avoid the difficulties that must be overcome to convey a pressure fluid that has a sufficiently high working pressure and that is available in a sufficient quantity from a drilling platform or ship on the water's surface to the ocean floor, located correspondingly at a great depth, the prior art (see U.S. Pat. No. 6,418,970 B1) discloses a device of the kind mentioned in the introduction for providing the hydraulic working pressure required for actuating the related deep-sea system in situ. The necessary hydraulic working pressure is generated by utilizing the surrounding pressure of the deep sea, which is the high deep water pressure. Specifically, the surrounding deep water pressure of the deep sea is applied to a piston apparatus inside a cylinder arrangement. The hydraulic pressure is generated by the achieved movement of the piston inside a pressure chamber of the cylinder arrangement.
Despite the advantages that are created due to the generation or in situ transfer of the working pressure, the operating properties of the known device are not satisfactory. The use of seawater for operating the cylinder arrangement poses problems in several regards. On the one hand, a contamination risk exists due to the penetration of sediment particles and the like, or of microorganisms that are introduced together with the seawater. On the other hand, the system is compromised due to the extremely corrosive effect of the seawater. To counteract the corrosion problem, the cylinder arrangement must be suitably lined with, and/or manufactured from, correspondingly corrosion-proof materials to reduce corrosion and/or the elevated friction coefficient with the piston movements due to deposits. Despite these measures, difficulties persist, due to salt water deposits, for example calcium stearate.